Magnetic random access memory (MRAM) is a non-volatile random access memory which gains popularity in recent years as potential replacement for dynamic random access memory (DRAM), static random access memory (SRAM) and flash. MRAM, for example, includes magnetic tunnel junction (MTJ) element which uses magnetic polarization to store information. For example, READ and WRITE operations of the MRAM device rely on the MTJ element. However, magnetic interferences can be a problem for MRAM devices. For instance, MTJ functions can be affected by an external magnetic field. The external magnetic field may come from sources of magnetic flux such as power lines, bar magnets, or the earth. The external magnetic fields not only distort magnetic signals within the MTJ memory, but also induce changes on electrical signals of the circuits. READ and WRITE operations in MRAM devices are inevitably affected by external magnetic fields. These cause reliability issues in MRAM devices.
Accordingly, it is desirable to provide reliable and cost effective wafer-level processing of magnetic shielding techniques to protect the MRAM chip from external magnetic fields. For certain applications, such as chip card, package level magnetic shielding may not be applicable due to package thickness (form factor) constraint. As such, there is a need for a die or chip-level magnetic shielding processed at, for example, the wafer-level.